Rapid Communications in Mass Spectrometry最新文献

{"title":"Deer Antler δ18O Records Desalination in Israel's Water Supply","authors":"Corrin Laposki,&nbsp;Audra Darcy,&nbsp;Noam Werner,&nbsp;Gideon Hartman","doi":"10.1002/rcm.70139","DOIUrl":"10.1002/rcm.70139","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Stable oxygen isotope ratios (<i>δ</i>¹⁸O) in mammalian tissues are widely used to reconstruct past climates, seasonal patterns, and animal origins. These analyses assume that animals drink local rainwater—an assumption now challenged by large-scale anthropogenic water management. Here we present a <i>δ</i>¹⁸O time series from Mesopotamian fallow deer (<i>Dama mesopotamica</i>) antler carbonate spanning 2006–2021, a period coinciding with the major expansion of desalinated water in Israel's national grid.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Antler samples were collected across 2006–2021, and carbonate <i>δ</i>¹⁸O values were measured using an automated carbonate preparation device (KIEL-III) coupled to a gas ratio mass spectrometer (Finnigan MAT 252) at the University of Arizona's Environmental Isotope Laboratory. Measurements were calibrated against repeated analyses of NBS-19 and NBS-18 standards; analytical precision was ±0.1‰ for <i>δ</i>¹⁸O (1σ).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Antler <i>δ</i>¹⁸O values show a systematic shift toward isotopically elevated compositions through time. This temporal trajectory closely tracks the sequential commissioning of five major reverse osmosis facilities between 2005 and 2015. One-way ANOVA confirmed significant differences in <i>δ</i>¹⁸O across pre-desalination, transitional, and post-expansion sample groups (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>F</mi>\u0000 </mrow>\u0000 <annotation>$$ F $$</annotation>\u0000 </semantics></math>(2,33) = 11.21, <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>p</mi>\u0000 </mrow>\u0000 <annotation>$$ p $$</annotation>\u0000 </semantics></math> &lt; 0.001).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>These findings demonstrate that anthropogenic water management can induce isotopic shifts in mammalian tissues that rival natural climatic variability, introducing systematic errors into provenance reconstructions. Researchers working with modern or recent historical faunal assemblages in water-managed landscapes should incorporate documented water supply histories into their interpretive frameworks alongside climatological isoscapes.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 19","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70139","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148519684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CO2 and N2O Emissions From Vehicles in Seoul Megacity, South Korea: Insights From Mixing Ratio and Stable Isotope Ratios","authors":"Jeongeun Kim,&nbsp;Jinho Ahn,&nbsp;Sambit Ghosh,&nbsp;Sakae Toyoda,&nbsp;Shinji Morimoto,&nbsp;Hyunsuk Choi,&nbsp;Jaehoen Jung,&nbsp;Hungyu Lee","doi":"10.1002/rcm.70094","DOIUrl":"10.1002/rcm.70094","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Vehicular traffic is a major source of anthropogenic greenhouse gases in megacities; however, real-world constraints on vehicle-derived N₂O emissions and their isotopic characteristics remain limited.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Air samples were collected from three tunnels and urban background sites (a university campus and mountain) in Seoul, South Korea. The CO₂ and N₂O mixing ratios and isotopic compositions (δ¹³C, δ¹⁸O of CO₂; δ¹⁵N^bulk, δ¹⁸O, and site preference of N₂O) were measured by gas chromatography and isotope ratio mass spectrometry, respectively. The vehicle-emitted isotopic endmembers were derived using Keeling plot analysis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The vehicular N₂O:CO₂ molar ratio was (4.8 ± 1.9) × 10⁻² (ppb:ppm). Scaling this ratio to Seoul's on-road CO₂ inventory yields an estimated annual N₂O emission of 163 ± 66 kt CO₂ equivalents, more than twice the current bottom-up estimate. Vehicle-emitted CO₂ exhibited isotopically homogeneous fossil fuel combustion δ¹³C signatures (−27.6‰ ± 0.4‰) and δ¹⁸O values (26.8‰ ± 0.5‰), and vehicular N₂O was characterized by low δ¹⁵N^bulk values (−6.5‰ ± 2.3‰), δ¹⁸O values (34.1‰ ± 2.2‰), and near-zero site preference (0.2‰ ± 7.3‰).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The integration of tunnel and tailpipe measurements with stable isotope analyses enables the direct quantification of greenhouse gas emissions from vehicles under real-world conditions. Vehicle-derived CO₂ exhibits a narrow and well-constrained δ¹³C signature, which is consistent with gasoline- and diesel-dominated fleets in Seoul, whereas N₂O isotopes reflect the formation processes associated with high-temperature combustion and catalytic after treatment. Furthermore, systematically lower δ¹⁸O values in vehicle-derived CO₂ and N₂O relative to the urban background identify a distinct oxygen-isotope fingerprint of traffic emissions, thereby establishing δ¹⁸O as a complementary tracer to traffic-related greenhouse gas quantification.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 18","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC13383353/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148519672","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Laboratory Reagents for Cleaning Modern Contamination on the δ15N Integrity of Nitrogen-Poor Samples","authors":"Kunmanee Bubphamanee,&nbsp;Andrew Schauer,&nbsp;Roger Buick","doi":"10.1002/rcm.70136","DOIUrl":"10.1002/rcm.70136","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Nitrogen isotope values have been widely used for tracing ancient biogeochemical processes, but contaminant-sensitive materials, such as Precambrian sedimentary rocks, meteorites, or returned extraterrestrial samples, often have low nitrogen levels and are thus vulnerable to modern organic contamination. However, the polluting effects of laboratory solvents commonly used for organic decontamination of such materials remain unquantified for nitrogen contents and isotopic ratios.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Four pre-treatment protocols using the common organic solvents dichloromethane (DCM), <i>n</i>-hexane, and ethanol were applied to powdered quartz controls to evaluate their pollution of nitrogen concentrations and isotopic compositions. The least polluting protocol was then applied to chert samples with low nitrogen contents to assess its effectiveness in recovering primary nitrogen signatures.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Comparison of total nitrogen contents before and after pre-treatments indicates that DCM introduced the most nitrogen pollution, followed by ethanol, with <i>n</i>-hexane causing the least. DCM-only and DCM with ethanol pre-treatments showed a large deviation of <i>δ</i>¹⁵N values compared to untreated controls, while the ethanol-only pre-treatment showed a positive shift in <i>δ</i>¹⁵N values. Both <i>n</i>-hexane-only and <i>n</i>-hexane with ethanol pre-treatments showed consistent <i>δ</i>¹⁵N values with the untreated controls. While <i>n</i>-hexane-only pre-treatment had the least effect on total nitrogen content and the nitrogen isotopic composition of the untreated controls, the use of double-solvent pre-treatment with differing polarities is recommended to address the broad range of modern contaminants found in nature.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>The <i>n</i>-hexane followed by ethanol pre-treatment provided the optimal outcome for pre-treatment and can effectively remove modern nitrogen contamination in samples with as little as 9 ppm total nitrogen without indigenous isotopic values being obscured by reagent-derived nitrogen pollution.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 19","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70136","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148468089","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep Learning Outperforms Descriptor-Based Classification of Food Items Using Chromatography–Mass Spectrometry Data","authors":"Mahmoud Elsayed,&nbsp;Islam H. El Azab,&nbsp;Hassan E. Abd Elsalam,&nbsp;Hussein A. K. Kyhoiesh","doi":"10.1002/rcm.70134","DOIUrl":"10.1002/rcm.70134","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Food classification and adulteration detection are challenged by the complexity of chemical matrices. Traditional descriptor-based methods fail to capture interactions in chromatography–mass spectrometry (CMS) data. This study compares a convolutional neural network (CNN) against a random forest (RF) baseline using engineered descriptors to classify 15 food items to demonstrate deep learning advantage for objective, scalable food authentication.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Three thousand CMS spectra is computationally simulated (200 per class) based on FooDB compound profiles. Six engineered descriptors (mean intensity, standard deviation, spectral entropy, etc.) are extracted for RF training. A SimpleCNN with two convolutional layers (32/64 filters, kernel size 5) followed by max-pooling, a fully connected layer (128 units, dropout 0.3), and softmax output is trained (Adam, lr = 0.001, 50 epochs). t-SNE and K-means (<i>k</i> = 5) visualize the chemical space, while adulteration are simulated by mixing corn syrup into honey spectra (10%–50% v/v).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The CNN achieves 93.1% accuracy, significantly outperforming RF (87.3%). t-SNE reveales five coherent clusters (silhouette coefficient = 0.71; Davies–Bouldin index = 0.43). Adulteration detection reaches 94.2% sensitivity and 96.8% specificity. The chemical similarity network identified novel pairings (e.g., chocolate–coffee, cosine similarity = 0.804) consistent with shared Maillard reaction products.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusion</h3>\u0000 \u0000 <p>End-to-end deep learning on CMS fingerprints substantially surpasses descriptor-based classification to provide a robust pipeline for food authentication, adulteration screening, and data-driven pairing discovery. Validation on experimentally acquired spectra remains a necessary next step.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 19","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148409761","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Comparative Study of MALDI MSI Versus DESI MSI Applied to Questioned Document Examination","authors":"Veronika Tibljas,&nbsp;Simona Francese,&nbsp;Marjory Da Costa Abreu,&nbsp;Charlotte Lefebvre,&nbsp;Robert Bradshaw","doi":"10.1002/rcm.70135","DOIUrl":"10.1002/rcm.70135","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>In forensic investigations, questioned document examination (QDE) provides critical information for document authentication and the detection of forgeries. Conventional QDE approaches often require separate analyses of inks and of any potential fingerprints. This study compares two mass spectrometry imaging (MSI) techniques for QDE, enabling the simultaneous analysis of inks and fingerprints deposited onto paper, providing chemical and biometric information from a single sample.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Two mock forgery samples containing two ballpoint pen inks, printed ink and latent fingerprints were each analysed using either desorption electrospray ionisation mass spectrometry imaging (DESI MSI) or matrix-assisted laser desorption/ionisation mass spectrometry imaging (MALDI MSI) and the results were compared. Analyses were conducted using state-of-the-art multi reflection time-of-flight (MRT) mass spectrometry instrumentation, providing high resolving power and sub-ppm mass accuracy.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Both techniques successfully differentiated between two blue ballpoint pen inks by detecting ink components present in one pen but absent from the other (despite them being optically indistinguishable). Chemical information associated with the deposited fingerprints was also successfully detected and mapped using both DESI MSI and MALDI MSI. However, MALDI MSI outperformed DESI MSI in terms of the clarity of biometric information obtained.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Overall, the strengths and limitations of DESI MSI and MALDI MSI for QDE were evaluated, demonstrating the potential of each technique for QDE. This assessment helps identify the most suitable approach for the analysis of this type of forensic casework by showing the benefits and reliability of each technique.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 19","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70135","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148409770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Serine Octamer Substitution Reactions With α-Hydroxy Acids","authors":"Keerthana Unni,&nbsp;Brison A. Shira,&nbsp;Dylan T. Holden,&nbsp;Thalappil Pradeep,&nbsp;R. Graham Cooks","doi":"10.1002/rcm.70133","DOIUrl":"10.1002/rcm.70133","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>The amino acid serine forms chiral magic number clusters, which can be studied using mass spectrometry (MS). Serine octamer clusters are also known to incorporate one or two nonserine monomers with serine monomers to make up the octamer.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>A Thermo LTQ ion trap mass spectrometer with nanoelectrospray ionization (nESI) was used to study cluster formation by both kinetically and energy-resolved methods. This study validates past observations on the homochiral preference of serine octamer during its association with other nonserine monomers.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>A substrate scope covering α-hydroxy acids and related molecules was studied. The chiral preference was investigated with tandem MS and the importance of salt bridge formation and α/β-carbon hydrogen bonding was recognized.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Weak interactions involving steric forces, salt bridges, ion–dipole interactions, and hydrogen bonds control stereoselective and chiroselective properties of the serine octamer cluster.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 18","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70133","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148366192","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cryogen-Aided Chromatographic Purification of Millimole Quantities of Methane for Spectroscopic Clumped Isotope Analysis","authors":"Nico Kueter,&nbsp;Jan G. C. Meissner,&nbsp;Naizhong Zhang,&nbsp;Léna Msonnereau,&nbsp;Lukas Emmenegger,&nbsp;Joachim Mohn,&nbsp;Stefano M. Bernasconi","doi":"10.1002/rcm.70114","DOIUrl":"10.1002/rcm.70114","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Quantum cascade laser absorption spectroscopy (QCLAS) is a fast and reliable method for analyzing the bulk (𝛿¹³C-CH₄, 𝛿D-CH₄) and clumped isotopic (∆¹³CH₃D and ∆¹²CH₂D₂) composition of methane. However, precise measurements of ∆¹²CH₂D₂ require 0.5 to 1.8 mmol of purified methane (equivalent to 15 to 40 mL at STP). We present a cryogen-aided preparative gas chromatography (GC) method with 1 h cycle time that quantitatively separates methane from complex gas mixtures containing N₂, O₂, Ar, CO₂, H₂O, and volatile higher alkanes.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>The method employs two sequential Carboxen 1000 columns, precooled to −10°C and subsequently ramped to 150°C in two heating steps, coupled with cryofocusing on charcoal and cryocollection on silica gel. The method performance was evaluated using a well-characterized in-house methane reference gas, either diluted in air–He matrices or stored in Exetainer vials for up to 3 weeks. Purification tests on thermogenic and biogenic methane samples assessed the repeatability of the purification method across different natural gases.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Cooling of the GC columns to −10°C achieves complete chromatographic purification of millimole quantities of methane from contaminant gasses. The processing introduces no measurable bulk (𝛿¹³C-CH₄, 𝛿-CH₄) and clumped-isotope (∆¹³CH₃D and ∆¹²CH₂D₂) fractionation within the 1σ repeatability of the QCLAS system. The repeatability of methane isotope measurements from natural gas samples is comparable to that obtained in tests using the well-characterized in-house reference gas.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>Chromatographic purification of millimole quantities of methane from synthetic and natural gas mixtures requires GC column cooling to at least −10°C to ensure sufficient separation from major air components. The developed method enables rapid and quantitative purification of up to 40 mL of methane without detectable isotope fractionation, demonstrating the applicability and robustness of the method for routine purification prior to QCLAS-based methane clumped-isotope analysis.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 18","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70114","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148358582","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Three New Calcium Formate Reference Materials for δ13C Measurements and a Redetermination of the R(13C/12C) Ratio for VPDB Based on Proton Nuclear Magnetic Resonance Measurements","authors":"David W. Hoffman,&nbsp;Cornelia Rasmussen,&nbsp;Arndt Schimmelmann,&nbsp;Lauren T. Reid,&nbsp;Haiping Qi,&nbsp;Tyler B. Coplen","doi":"10.1002/rcm.70132","DOIUrl":"10.1002/rcm.70132","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Isotope ratio mass spectrometry (IRMS) and proton nuclear magnetic resonance (¹H NMR) spectroscopy are independent techniques for determining the isotope ratio <i>R</i>(¹³C/¹²C) in organic compounds. However, the lack of suitable reference materials has limited intercalibration of results from these methods.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Methods</h3>\u0000 \u0000 <p>Three high-purity calcium formate isotopic reference materials were developed, each ideal for accurate isotope ratio measurements by both ¹H NMR and isotope-ratio mass spectrometry (IRMS). For each material, <i>R</i>(¹³C/¹²C) was determined by ¹H NMR, and the relative isotope abundance (<i>δ</i>¹³C_VPDB-LSVEC) by IRMS. The combined IRMS and NMR results were used to determine the <i>R</i>(¹³C/¹²C) value of Vienna Peedee belemnite (VPDB).</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>The combined datasets yield a value for <i>R</i>(¹³C/¹²C) of 0.0111050 ± 0.0000047 (<i>k</i> = 2) for VPDB, which is 6.7‰ lower than the commonly cited value of 0.011180, but similar to other recent determinations. These three calcium formate reference materials exhibit high accuracy across both analytical methods and provide robust tools for instrument calibration, method validation, and inter-laboratory comparison in carbon stable isotope ratio analysis.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>An accurate <i>R</i>(¹³C/¹²C) value for VPDB strengthens the link between relative (<i>δ</i>¹³C_VPDB-LSVEC) values from IRMS and <i>R</i>(¹³C/¹²C) isotope ratios from NMR and other techniques. These three calcium formate isotopic reference materials (USGS106, USGS107, and USGS108) are available from the US Geological Survey and provide reference materials for calibration, method validation, and inter-laboratory comparison in carbon isotope ratio analysis.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 18","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70132","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148358522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reaffirming the Consistency of the Original Stock of NBS 19 Limestone and Its Byproduct With Finer Grain Size for δ13C and δ18O Calibrations—Both Distributed Internationally","authors":"Haiping Qi,&nbsp;Tyler B. Coplen,&nbsp;Lauren T. Reid,&nbsp;Stanley J. Mroczkowski","doi":"10.1002/rcm.70131","DOIUrl":"10.1002/rcm.70131","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 \u0000 <h3> Rationale</h3>\u0000 \u0000 <p>Approximately 3–4 kg of NBS 19 limestone, prepared in 1982 by the U.S. Geological Survey (USGS), serves as a primary reference for the carbon isotope scales VPDB and VPDB-LSVEC and the oxygen isotope scale VPDB. Its consensus values are +1.95‰ for <i>δ</i>¹³C and −2.2‰ for <i>δ</i>¹⁸O measurements. After more than three decades of distribution, the number of units labeled “NBS 19” shrunk substantially, and the remaining material was quarantined, with a small fraction retained at the USGS and a larger fraction entrusted to the International Atomic Energy Agency (IAEA) for secure storage. Given the critical role of NBS 19, verifying the integrity of its <i>δ</i>¹³C and <i>δ</i>¹⁸O values across these storage locations is essential.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Method</h3>\u0000 \u0000 <p>Samples from IAEA and USGS stock materials were selected to ensure traceability of carbon and oxygen isotopes to NBS 19 distribution units from various storage locations. To achieve this, distribution units labeled as NBS 19 from both the IAEA and the National Institute of Standards and Technology (NIST) were included. During evaluation, two distinct grain sizes were identified within these units. Grain size was assessed using sieves on five selected samples. The <i>δ</i>¹³C and <i>δ</i>¹⁸O values of finer and coarser fractions (both labeled NBS 19) were measured at USGS using continuous-flow isotope-ratio mass spectrometry on 100- and 200-μg samples.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Results</h3>\u0000 \u0000 <p>Expanded 95% measurement uncertainties (<i>k</i> = 2) for <i>δ</i>¹³C and <i>δ</i>¹⁸O determinations are 0.027‰ and 0.038‰ or better, respectively, for quarantined NBS 19 stocks and finer byproduct calcite, which we term “NBS-19 byproduct,” regardless of storage location. Between the 1990s and circa 2011, NBS-19 byproduct labeled “NBS 19,” distributed by NIST and the IAEA, shows these findings.</p>\u0000 </section>\u0000 \u0000 <section>\u0000 \u0000 <h3> Conclusions</h3>\u0000 \u0000 <p>NBS 19 primary isotopic reference material should be used for calibration of new isotopic reference materials rather than NBS-19 byproduct secondary isotopic reference material.</p>\u0000 </section>\u0000 </div>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 18","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70131","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148358598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to “Zinc/Silver-Based Hydrogen Sulfide Trapping as an Alternative to Cadmium for Sulfur Stable Isotope Analysis”","authors":"","doi":"10.1002/rcm.70107","DOIUrl":"https://doi.org/10.1002/rcm.70107","url":null,"abstract":"<p>\u0000 <span>D. Ure</span>, <span>K. Dominato</span>, <span>M. Beaton</span>, and <span>S. Mundle</span>, “ <span>Zinc/Silver-Based Hydrogen Sulfide Trapping as an Alternative to Cadmium for Sulfur Stable Isotope Analysis</span>,” <i>Rapid Communications in Mass Spectrometry</i> <span>39</span>, no. <span>22</span> (<span>2025</span>): e10120, https://doi.org/10.1002/rcm.10120.\u0000 </p><p>In the version of this article initially published, Schemes 1 and 2 were incorrect. The correct versions are as follows:</p><p>H₂S _(g) + Cd²⁺ _(aq) → CdS _(s) + 2H⁺ _(aq)</p><p>CdS _(s) + 2Ag⁺ _(aq) → Cd²⁺ _(aq) + Ag₂S _(s)</p><p><b>SCHEME 1</b>|H₂S conversion to Ag₂S in the Cd-based method.</p><p>H₂S _(g) + Zn²⁺ _(aq) → ZnS _(s) + 2H⁺ _(aq)</p><p>2Ag⁺ _(aq) + ZnS _(s) → Zn²⁺ _(aq) + Ag₂S _(s)</p><p><b>SCHEME 2|</b>H₂S conversion to Ag₂S in Zn/Ag-trapping solutions. Note that these steps occur in parallel within the same reaction flask.</p><p>We apologize for these errors.</p>","PeriodicalId":225,"journal":{"name":"Rapid Communications in Mass Spectrometry","volume":"40 18","pages":""},"PeriodicalIF":1.8,"publicationDate":"2026-06-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/rcm.70107","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148343028","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}